Numerical investigation of the load capacity of a gas journal bearing of finite length with end seals

2009 ◽  
Vol 44 (6) ◽  
pp. 836-841 ◽  
Author(s):  
V. I. Grabovskii
Keyword(s):  
Numerical Investigation ◽  
Finite Length ◽  
Journal Bearing ◽  
Load Capacity ◽  
Gas Journal Bearing

Static and Dynamic Characteristics of Externally Pressurized Porous Gas Journal Bearing With Four Degrees-of-Freedom

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Shuyun Jiang ◽  
Shengye Lin ◽  
Chundong Xu
Keyword(s):  
Dynamic Characteristics ◽  
Degrees Of Freedom ◽  
Reynolds Equation ◽  
Static Load ◽  
Journal Bearing ◽  
Load Capacity ◽  
Linear Perturbation ◽  
Static And Dynamic Characteristics ◽  
Bearing Number ◽  
Gas Journal Bearing

This paper studies the static and dynamic coefficients of an externally pressurized porous gas journal bearing. The finite difference method is used to solve the Reynolds equation of the bearing to obtain the static load capacity. The linear perturbation method is adopted to derive the perturbation equations considering four degrees-of-freedom (4DOF), namely, the translational movements in x and y directions and the rotational movements around x and y directions. The effects of various parameters on the dynamic behaviors of the journal bearing are studied. These parameters include the bearing number, the supply pressure, the feeding parameter, the length-to-diameter ratio, the porosity parameter, the eccentricity ratio, and tilting angles. Simulated results prove that the proposed method is valid in estimating the static and dynamic characteristics of a porous gas journal bearing with 4DOF.

Theory and Experiments of Squeeze-Film Gas Bearings: Part 1—Cylindrical Journal Bearing

1966 ◽  
Vol 88 (1) ◽  
pp. 191-198 ◽  
Author(s):  
C. H. T. Pan ◽  
S. B. Malanoski ◽  
P. H. Broussard ◽  
J. L. Burch
Keyword(s):  
Experimental Data ◽  
Journal Bearing ◽  
Approximate Analytical Solution ◽  
Load Capacity ◽  
Squeeze Film ◽  
Radial Load ◽  
Radial Stiffness ◽  
Theoretical Predictions ◽  
Gas Journal Bearing ◽  
Theory And Experiments

An asymptotic analysis for the cylindrical squeeze-film gas journal bearing has been formulated. An approximate analytical solution is presented. Load-deflection experiments have been performed on a double-film, squeeze-film gas journal bearing. The experimental data confirm the theoretical predictions. Design curves are given for the steady-state radial load capacity and radial stiffness of the cylindrical gas journal bearing.

scholarly journals Numerical analysis on the performance characteristics of a new gas journal bearing by using finite difference method

2021 ◽  
Vol 13 (6) ◽  
pp. 168781402110280
Author(s):  
Yuntang Li ◽  
Ruirui Li ◽  
Yueliang Ye ◽  
Xiaolu Li ◽  
Yuan Chen
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Journal Bearing ◽  
Load Capacity ◽  
Linear Perturbation ◽  
Eccentricity Ratio ◽  
Dynamic Performances ◽  
The Stability ◽  
Gas Journal Bearing

This paper proposes a novel gas journal bearing in which orifices are different in diameter and distribute unevenly. Finite Difference Method (FDM) combined with Linear Perturbation Method (LPM) is used to solve the unsteady-state Reynolds equation of the flow field in the bearing clearance. Moreover, four types of bearing structures are used to discuss the effects of orifices different in diameter and uneven distribution on the bearing performance. The results demonstrate that the new bearing has better static and dynamic performances compared with those of traditional bearing in which orifices are equal in diameter and distribute evenly. Moreover, thin gas film thickness, high supply pressure, and large eccentricity ratio are hopeful for improving load capacity of the new bearing. Furthermore, the stability of the novel bearing is improved if eccentricity ratio is 0.25–0.3.

Static Characteristics of a Slot-Entry Gas Journal Bearing With Feeding Holes

1988 ◽  
Vol 110 (4) ◽  
pp. 587-591 ◽  
Author(s):  
S. Yoshimoto
Keyword(s):  
Gas Flow ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Viscous Resistance ◽  
Narrow Gap ◽  
Static Characteristics ◽  
Theoretical Predictions ◽  
The Finite Difference Method ◽  
Gas Journal Bearing

This paper describes the static characteristics of a slot-entry gas journal bearing with feeding holes. Gas flow in this bearing is restricted first by inflow resistance when gas rapidly flows into the narrow gap of the slot region from isolated feeding holes, and then, restricted more by viscous resistance in the slot region. Therefore, the maximum load capacity and stiffness in this type of bearing can be easily obtained even in a very small bearing clearance of less than 10 μm because gas flow entering the journal can be restricted to a very small amount. Here, the static characteristics of this type of bearings are determined numerically by using the finite difference method. The validity of the theoretical predictions is confirmed by comparison with the experimental results.

Nonlinear Numerical Investigation Around Instability Point of the Flexible Rotor Supported by the Journal Bearing

2017 ◽  
Author(s):  
Mugen Ito ◽  
Tsuyoshi Inoue
Keyword(s):  
Numerical Simulation ◽  
Hopf Bifurcation ◽  
Numerical Investigation ◽  
Finite Length ◽  
Journal Bearing ◽  
Rotating Machinery ◽  
Flexible Rotor ◽  
Rotor Systems ◽  
Instability Point ◽  
Nonlinear Numerical Simulation

Rotating machinery supported by the journal bearing may be subject to instability. This instability is classified as the Hopf bifurcation. Either a sub-critical bifurcation or super-critical bifurcation appears depending on the parameters of rotor systems. Conventionally, an infinitely short journal bearing model was used for the investigation of this bifurcation. In this paper, the force transmitted by the oil film of the journal bearing is represented by the finite length model. Nonlinear numerical simulation is performed at around instability point of the flexible rotor supported by the journal bearing. The bifurcation characteristic and the change of bifurcation type are investigated when the ratio L / D, which is the ratio of bearing length L to the bearing diameter D, increases.

scholarly journals Numerical investigation on dynamic characteristics of hydrodynamic bearing

2017 ◽  
Vol 21 (suppl. 1) ◽  
pp. 201-208 ◽  
Author(s):  
Liangliang Li ◽  
Yunzhu Li ◽  
Yonghui Xie
Keyword(s):  
Steady State ◽  
Numerical Investigation ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Load Capacity ◽  
Transient State ◽  
Diameter Ratio ◽  
Hydrodynamic Bearing ◽  
Stiffness Coefficients

In this paper, both the steady-state and transient-state of the films flow are investigated by CFD. The journal bearing dynamic characteristics such as the load capacity, damping and stiffness coefficients for several eccentricity, and length over diameter ratio (L/D) are obtained and compared with each other in different working conditions. Furthermore, the variation of various research parameters with eccentricity and L/D are also illustrated in detail.

Extension of the Patir-Cheng Flow Simulation of a Rough Surface Bearing to a Compressible Lubricant

1982 ◽  
Vol 24 (4) ◽  
pp. 209-214
Author(s):  
B. C. Majumdar ◽  
B. J. Hamrock
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Roughness Parameter ◽  
Flow Simulation ◽  
Surface Structures ◽  
Surface Pattern ◽  
Hydrodynamic Load ◽  
Gas Journal Bearing ◽  
Compressible Lubricant

It is shown that the average Reynolds equation for rough surfaces using an incompressible lubricant derived by Patir and Cheng (1)§ can be used for a compressible lubricant if the surface structures of both surfaces are the same. The average Reynolds equation is applied to an infinitely long gas journal bearing to find the hydrodynamic load capacity. The effect of the roughness parameter and the surface pattern parameter on the hydrodynamic load is also investigated.

scholarly journals Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

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